Is the basic principle of Pat Martino's Minor Conversion Concept anything more than simply altering melodic minor scales?
The minor concept ... is about improvising and how to think about scales. Martino basically reduces most chord scales to their relative (melodic) minor scale. So over an altered E7 chord he would think F minor (F melodic minor equals the E altered scale). Similarly, over a Dm7(b5) chord he would also think in F (melodic) minor, effectively using locrian ♮2 over the half-diminished chord.
So the Minor Concept is about altering a single base scale to fit all the scales a musician uses. This is a way of playing all 12 scales in any position on the fretboard. Many guitar players instead use an altered pentatonic scale with added color tones. Or they use the CAGED system. Either one of these I find more useful than the Minor Concept but it may work for some people.